Police are investigating a report that a teenage girl was raped in the stairwell of a Brooklyn public school while another student watched.

The 15-year-old student was in the stairwell of J.H.S. 218 James P. Sinnott on Fountain Avenue in East New York around 12:45 p.m. Nov. 21 when she was sexually assaulted by a 16-year-old male student, all while another boy kept watch, police and sources said.

The student reported the incident Wednesday night. Police say no arrests have yet been made.

The Fountain Avenue campus also houses The School for Classics and nonprofit youth advocacy group Tomorrow’s Leaders NYC.

The girl told investigators 18-year-old Jevon Martin lured her into the back of a stairwell by grabbing her jacket and backpack, before pushing her to the floor and raping her on the morning of Dec. 4.

Martin was arraigned in Manhattan Criminal Court for alleged rape, sexual misconduct and endangering the welfare of a child. He was held on $10,000 bail.